Nope, not that crazy. Though some people just use a pyrex pan, which would probably suffice.
3x layers of 1/2" drywall, drywall in the lid doesnt seal with the drywall in the base, and there is a brass vent stuffed with aluminum screening to arrest any flame as hot gasses would vent. Working on adding a panelmount XLR for feeding power though, and even a usb connection for the datalogging portion of the charger. Hooray "I'm bored... it'd be a good idea if..." projects.